As shown in FIG. 1, a prior art receiver-transmitter 10 is composed of a yoke iron 11, a magnet 13, and a magnetic pole piece 15. According to the conventional practice of assembling the receiver-transmitter 10, the magnet 13 and the magnetic pole piece 15 are first held together by means of an adhesive 17. After the adhesive 17 located between the magnet 13 and the magnetic pole piece 15 is dried and hardened, the adhesive 17 is applied to a recess 18 before the magnet 13 and the magnetic pole piece 15 are located at the center of the recess 18 by means of a control device 19. After the adhesive 17 in the recess 18 is dried and hardened, the final assembling work is administered. Such a prior art receiver-transmitter 10 as described above has shortcomings, which are expounded hereinafter.
The process of making the receiver-transmitter 10 is time-consuming in view of the fact that certain steps of the process can not be carried out before the adhesive 17 is dried and hardened.
The amount of the adhesive 17 deposited in the recess 18 must be precise so as to ensure that the magnet 13 and the magnetic pole piece 15 are securely located in the recess 18 with precision.
The quality of the receiver-transmitter 10 is dependent on the quality of the adhesive 17 in view of the fact that the quality of the adhesive 17 plays an important role on determining the holding strength by which the magnet 13 and the magnetic pole piece 15 are held together.
It is difficult to detect the potential problems that are associated with the component parts of a defective receiver-transmitter 10.
The process of making the prior art receiver-transmitter 10 is complicated by the use of the control device 19 for locating the component parts of the receiver-transmitter 10.